The IRS also recognizes that "the two organizations [a (c)(3) and a (c)(4)] may share staff, facilities, or other expenses or ...conduct joint activities requiring an allocation of income and expenses,” but the allocation must be carefully reviewed to ensure that it is appropriate and that the resources of the IRC 501(c)(3) organization are not used to support the political campaign activity of the IRC 501(c)(4) organization or its PAC. 16 |